Hot-headed, hard-hitting defensive standout Sean Taylor of the NFL’s Washington Redskins was fighting for his life last night after surgery for a gunshot wound inflicted by a thug who broke into his suburban Miami home.

The 24-year-old safety flat-lined twice during the operation to repair damage to a femoral artery in his leg, and lost a “substantial” amount of blood, raising concerns about the effect on his brain, according to his former lawyer, Richard Sharpstein, a family friend.

Sharpstein said relatives and doctors were gratified that Taylor was responsive last night for the first time; he squeezed the hand of a nurse.

“It was touch and go all day,” Sharpstein told The Post. “Things were pretty bleak. We hope he’s as strong here as he was on the football field.”

Sharpstein said Taylor’s girlfriend, the mother of his 18-month-old daughter, was at his bedside.

“For her, it was even more dramatic,” Sharpstein said. “She heard gunshots – one went into the wall of the bedroom and one went into Sean’s leg. When she got out of bed, he was on the ground . . . basically unconscious.”

Taylor, who had missed the last two Redskin games because of a knee injury, was at the house in upscale Palmetto Bay recuperating when the gunman burst into the bedroom at about 1:45 a.m. and opened fire.

“It could have been a possible burglary; it could have been a possible robbery,” said police Lt. Nancy Perez said. “It has not been confirmed as yet.”

According to Sharpstein, cops were investigating whether the violence was connected to a burglary at Taylor’s mansion eight days earlier when no one was home – or a 2005 misdemeanor assault and battery case in which the lawyer defended Taylor.

In Ashburn, Va., Taylor’s teammates were stunned.

“This is not just a member of the Washington Redskins, but we’re talking about a dad, a brother, a friend of ours, and that’s where we’re at with this right now,” said a distraught fellow Redskin safety Pierson Prioleau.

Taylor has been in trouble several times since he was drafted as the No. 5 overall pick in 2004.

He has been fined at least seven times during his professional career for late hits and other infractions, including a $17,000 fine for spitting in the face of Tampa Bay running back Michael Pittman during a playoff game in January 2006.

He also was fined $25,000 for skipping a mandatory rookie symposium shortly after he was drafted out of the University of Miami.

In 2005, Taylor was accused of pulling a gun on a man and repeatedly hitting him during a fight that broke out after Taylor and some friends went looking for the people who had allegedly stolen his all-terrain vehicles.

Taylor, represented by Sharpstein, reached a deal with prosecutors last year after they agreed to drop felony charges against him. With Post Wire Services